<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<style>
    .outer {
        width: 200px;
        height: 200px;
        /*background-color: #bbffaa;*/
        position: absolute;
        left: 50%;
        top: 50%;
        transform: translate(-50%,-50%);
    }
    .row1 {
        background-color: red;
        height: 50%;
        width: 40%;
        /*品上面的口居中*/
        margin: 0 auto;
    }
    .row2 {
        height: 50%;
        /*background-color: purple;*/

        margin-top: 10px;
    }
    .row2 .row21 ,.row22{
        width: 40%;
        height: 100%;
        float: left;
        background-color: lime;
    }
    .row22 {
        float: right;
    }
</style>
<body>
<div class="outer">
    <div class="row1"></div>
    <div class="row2">
        <div class="row21"></div>
        <div class="row22"></div>
    </div>
</div>
</body>
</html>
